U.S. patent application number 16/763582 was filed with the patent office on 2020-09-10 for fiber application head with flexible roller provided with an anti-adherent sheath.
This patent application is currently assigned to CORIOLIS GROUP. The applicant listed for this patent is CORIOLIS GROUP. Invention is credited to Johann CAFFIAU, Alexander HAMLYN, Jean-Philippe WEBER.
Application Number | 20200282667 16/763582 |
Document ID | / |
Family ID | 1000004870836 |
Filed Date | 2020-09-10 |
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United States Patent
Application |
20200282667 |
Kind Code |
A1 |
CAFFIAU; Johann ; et
al. |
September 10, 2020 |
FIBER APPLICATION HEAD WITH FLEXIBLE ROLLER PROVIDED WITH AN
ANTI-ADHERENT SHEATH
Abstract
The present application relates notably to a fibre application
head for producing composite material parts, comprising a
compacting system comprising a compacting roller (2) comprising a
rigid central tube (4) and at least one cylindrical part (3) made
of a flexible material and assembled on said central tube, and an
anti-adherent sheath (6) covering the cylindrical part, and a
heating system (9) that is able to emit thermal radiation in the
direction of the fibre(s). Said anti-adherent sheath has lateral
portions (61) extending beyond the cylindrical surface (33) of the
cylindrical part in the direction of the rotation axis of the
roller, the assembly of said anti-adherent sheath to said
cylindrical part being carried out by said lateral portions.
Inventors: |
CAFFIAU; Johann; (Hennebont,
FR) ; WEBER; Jean-Philippe; (Ploemeur, FR) ;
HAMLYN; Alexander; (Ploemeur, FR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
CORIOLIS GROUP |
Queven |
|
FR |
|
|
Assignee: |
CORIOLIS GROUP
Queven
FR
|
Family ID: |
1000004870836 |
Appl. No.: |
16/763582 |
Filed: |
November 9, 2018 |
PCT Filed: |
November 9, 2018 |
PCT NO: |
PCT/FR2018/000245 |
371 Date: |
May 13, 2020 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B29C 70/384 20130101;
B32B 2260/046 20130101; B32B 7/028 20190101; B32B 2260/023
20130101; B32B 2307/736 20130101; B29K 2105/08 20130101; B32B 7/022
20190101; B32B 1/08 20130101; B32B 25/08 20130101; B32B 7/04
20130101 |
International
Class: |
B29C 70/38 20060101
B29C070/38; B32B 1/08 20060101 B32B001/08; B32B 25/08 20060101
B32B025/08; B32B 7/022 20060101 B32B007/022; B32B 7/04 20060101
B32B007/04; B32B 7/028 20060101 B32B007/028 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 13, 2017 |
FR |
1701172 |
Claims
1. Fibre application head for producing composite material parts,
comprising a compacting system comprising a compacting roller (2,
102, 202, 302, 402, 502), for the application of one or more
fibres, onto an application surface (S), said compacting roller
comprising a rigid central tube (4) and at least one cylindrical
part (3, 103, 203, 403, 503) made of a flexible material,
elastically deformable, assembled on said central tube, and an
anti-adherent sheath (6, 106, 206, 406, 506) covering the
cylindrical part, and a heating system (9) capable of emitting
thermal radiation in the direction of the fibre or fibres,
characterized in that said anti-adherent sheath has lateral
portions (61, 161, 261, 461, 561) extending beyond the cylindrical
surface (33) of is the cylindrical part in the direction of the
rotation axis (A) of the roller, the assembly of said anti-adherent
sheath to said cylindrical part being carried out by said lateral
portions.
2. Head according to claim 1, characterized in that said
anti-adherent sheath (6, 106, 206, 406, 506) is thermoformed onto
the cylindrical part, the thermoformed lateral portions ensuring at
least partially the blocking of the sheath in rotation and in
translation.
3. Head according to claim 1 or 2, characterized in that said
central tube (4) is provided with radial holes (41), said
cylindrical part of flexible material having fluid communication
means (32) capable of putting said radial holes in fluid
communication with the external cylindrical surface (33) of the
cylindrical part, said head comprising thermal regulation means
capable of injecting a thermal regulation gas flow, into the
internal passage of the central tube, said roller comprises a
draining intermediate layer (5, 105, 205, 405, 505) interposed
between the anti-adherent sheath and the cylindrical part, said
intermediate layer ensuring the evacuation of the thermal
regulation fluid through the lateral faces of the roller.
4. Head according to claim 3, characterized in that said
intermediate layer (5, 105, 205, 405, 505) comprises glass
fibres.
5. Head according to claim 3 or 4, characterized in that the
intermediate layer (5, 105, 205, 405, 505) has end portions (51,
151, 251, 451, 551) extending beyond the cylindrical surface (33)
of the cylindrical part.
6. Head according to one of claims 1 to 5, characterized in that
each lateral portion (61, 161, 261, 461, 561) of the sheath is
assembled by its annular end section to mechanical assembly means
(271, 272; 371; 471, 472).
7. Head according to claim 5, characterized in that each lateral
portion (51, 151, 251, 451, 551) of the intermediate layer is
assembled by its annular end section to mechanical assembly means
(271, 272; 371; 471, 472; 571).
8. Head according to one of claim 6 or 7, characterized in that the
mechanical means comprises two washers (271, 272; 371; 471, 472),
assembled to one another by assembly means (273, 373, 473), and
between which the end section of the sheath and/or of the
intermediate is layer is enclosed.
9. Head according to one of claims 1 to 8, characterized in that
the roller has at each end a portion (135, 235) defining a curved
or inclined surface arranged in the extension of the cylindrical
surface (33).
10. Head according to one of claims 1 to 9, characterized in that
it comprises a laser type heating system capable of emitting a
laser beam in the direction of the contact zone between the roller
and a layup surface.
11. Method for manufacturing a composite material part comprising
the application of continuous fibres onto an application surface,
characterized in that the application of fibres is carried out by
means of a fibre application head according to one of claims 1 to
10, by relative movement of the application head in relation to the
layup surface along layup trajectories.
Description
[0001] The present invention relates to a fibre application head
for a fibre application machine for producing composite material
parts, and more particularly to a so-called fibre placement head
equipped with a particular application roller. The present
invention also relates to a method for manufacturing parts made of
composite material by means of a corresponding application
head.
[0002] There are known fibre application machines, commonly called
fibre placement machines, for the application by contact onto a
layup tool, such as a male or female mold, of a wide band formed of
several continuous flat fibres, of ribbon type, dry or impregnated
with thermosetting or thermoplastic resin, in particular carbon
fibres is consisting of a multitude of carbon threads or
filaments.
[0003] These machines are used to produce preforms formed of
several superposed plies, each ply being formed by laying up onto
the mold of one or more bands side by side. In the case of a layup
of fibres pre-impregnated with thermoplastic or thermosetting
resin, typically of a quantity of at least 40% in weight, the
pre-impregnated preform obtained after laying up is hardened or
polymerized by passing it through an oven to obtain a composite
material part. In the case of so-called dry fibres, which are not
pre-impregnated with resins, the fibres comprise a reduced quantity
of so-called bonding resin, also called a binder, generally a
thermoplastic resin, in a quantity of less than or equal to 5% in
weight, to give a tackiness to the fibres during the layup. After
layup, the so-called dry preform is subjected to a resin injection
or infusion operation before the curing step.
[0004] These machines, such as described in the patent document
WO2006/092514, typically comprise a fibre application head, a
system for moving said head, fibre storage means, and fibre
conveying means for conveying the fibres from said storage means to
the head. The head typically comprises an application roller, also
called a compacting roller, intended to come into contact with the
mold for applying the band, and means for guiding the fibres on
said application roller.
[0005] The head generally further comprises a heating system for
heating the fibres. The compacting roller presses the band of
fibres against the application surface of the mold, or against the
band(s) of fibres previously applied, in order to facilitate the
adhesion of the applied bands to each other, as well as to
progressively discharge the air trapped between the laid bands. The
heating system ensures the heating of the bands of fibres to be
applied, and/or of the mold or bands already applied upstream of
the compacting roller, just before the compacting of the band, in
order to at least soften the pre-impregnation resin or bonding
resin, and thus promote adhesion of the bands to one another.
[0006] In the case of thermosetting resins, the pre-impregnated
fibers are simply heated to soften them, typically at temperatures
of about 40.degree. C. The heating system typically comprises an
infrared heating system comprising one or more infrared lamps.
[0007] In the case of thermoplastic resins, the fibers
pre-impregnated or having a binder must be heated at higher
temperatures, at least up to the resin melting temperature, being
of about 200.degree. C. for nylon type resins, and up to about
400.degree. C. for PEEK type resins.
[0008] To achieve these higher temperatures, hot air torch systems
have been proposed, and more recently laser type heating systems to
achieve accurate and concentrated heating. Due to the higher
heating temperatures, the fibre placement heads are typically
equipped with metallic compacting rollers, resistant to heat, which
can furthermore be cooled by the interior via a water circuit. To
be able to adapt itself to the profile of the application surface,
segmented metallic compacting rollers have been proposed,
comprising several roller segments independently mounted side by
side on a same axle, each segment being radially moveable and in an
independent manner, and being elastically biased against the
application surface. These segmented metallic rollers have proven
however to be complex in structure and implementation.
[0009] Flexible rollers formed from a so-called high temperature
elastomer, including a thermal stabilizer, are also used. These
rollers generally comprise an anti-adherent sheath heat-shrunk and
glued to the cylinder made of elastomeric material, as described in
patent documents FR 2948058 and FR 3009512. To cool them, it has
been proposed to equip the placement heads with a cooling system
capable of delivering an air flow to cool the roller from the
outside or from the inside, as described in the patent document FR
2948058. Despite these cooling systems, flexible rollers can have a
tendency to deteriorate when using thermoplastic resins. Depending
on the heating temperatures used, the anti-adherent sheath may tend
to degrade quickly. Laser heating can tend to deteriorate the glue
used for gluing the sheath and lead to a disassembling of the
sheath and the cylinder of flexible material. Furthermore, the
deteriorated adhesive layer absorbs laser radiation and can rise to
high temperatures which can deteriorate the sheath.
[0010] During layup, combustion of the impregnation resin of the
fibres may occur. The combustion fumes tend to form deposits on the
sheath. In addition to the problem of fouling the sheath, these
deposits absorb laser radiation and can lead to the destruction of
the sheath.
[0011] In document FR 3009510, it has been proposed to provide
blowing is nozzles to diffuse an inert gas previously heated, such
as nitrogen, to locally form a protective atmosphere and to avoid
oxidation of the resins. This diffusion of nitrogen represents a
significant cost. Furthermore, this diffusion of nitrogen does not
allow the presence of an operator in the layup cell during layup,
and requires a renewal of the air in the cell before access is
allowed.
[0012] The aim of the present invention is to propose a solution to
overcome at least one of the aforementioned drawbacks, which in
particular enables the use of a wide variety of resins, both
thermosetting and thermoplastic, with a substantially uniform
compaction of the applied band, and which is simple in design and
construction.
[0013] To this end, the present invention provides a fibre
application head for producing composite material parts, comprising
[0014] a compacting system comprising a compacting roller, also
called an application roller, for applying one or more fibres, in
particular a band formed of one or more flat fibres, onto an
application surface, said compacting roller comprising a rigid
central tube by which said roller is rotationally mounted on a
support structure of the head and at least one cylindrical part
made of a flexible material, elastically deformable, assembled
coaxially, directly or indirectly, on said central tube, and an
anti-adherent sheath covering the cylindrical part, and [0015] a
heating system capable of emitting thermal radiation in the
direction of the fibre or fibres in the direction of the band,
preferably just before the application by the application
roller,
[0016] characterized in that said anti-adherent sheath has lateral
portions extending beyond the cylindrical surface of the
cylindrical part in the direction of the rotation axis of the
roller, the assembly of said anti-adherent sheath to said
cylindrical part being carried out by said lateral portions, said
lateral portions effecting a translational and rotational blocking
of the sheath in relation to said cylindrical part.
[0017] According to the invention, the protective sheath is
assembled by lateral portions outside the heating zone. This
assembly allows to avoid a gluing of the sheath in the heating zone
and therefore to avoid any risk of deterioration of the sheath due
to a deterioration of the glue due to the radiation.
[0018] The use of a roller provided with such a sheath according to
the invention makes it possible to obtain a flexible thermally
stable compacting roller usable for the application of fibres at
high temperatures, in particular above 400.degree. C., in
particular for the application of fibres impregnated with
thermoplastic resins. The head according to the invention, which
comprises a compacting roller of simple design, offers the
possibility of using a wide variety of thermosetting or
thermoplastic resins combined with a wide variety of fibres,
synthetic or natural, hybrid or not, in particular fibres commonly
used in the field of composites, such as glass fibres, carbon,
quartz, and aramid fibres.
[0019] According to one embodiment, said compacting roller
comprises a cylindrical part made of an elastomeric material,
preferably unexpanded, for example a silicone or a polyurethane,
preferably made of silicone, preferably having a hardness of
between 25 Shore A and 80 Shore A, preferably at least 40 Shore A,
in order to guarantee a good resistance of the sheath over
time.
[0020] According to one embodiment, the compacting roller comprises
a cylindrical part of foam, for example an expanded elastomer such
as a polyurethane foam, preferably having a density between 200
kg/m.sup.3 and 500 kg/m.sup.3.
[0021] Said anti-adherent sheath is advantageously formed from a
fluoropolymer, preferably a fluoropolymer chosen from the group
consisting of a polytetrafluoroethylene (PTFE), a perfluoroalkoxy
(PFA), a fluorinated ethylene propylene (FEP), an ethylene
tetrafluoroethylene (ETFE), preferably a PFA or FEP, and a
fluoroelastomer, for example an FPM, FFPM or FEPM or a
polyimide.
[0022] According to one embodiment, said anti-adherent sheath is
thermoformed on the cylindrical part, preferably heat-shrunk, the
thermoformed lateral portions ensuring at least partially the
blocking of the sheath in rotation and in translation. The use of a
heat-shrinkable sheath enables a simple and rapid assembly of the
sheath starting from a sheath in the form of a tube which is
subsequently heat-shrunk on the cylindrical part.
[0023] According to one embodiment, said central tube is provided
with radial holes, said cylindrical part of flexible material
having fluid communication means capable of putting said radial
holes in fluid communication with the external cylindrical surface
of the cylindrical part, said head comprising thermal regulation
means capable of injecting a thermal regulation gas flow,
advantageously a gas at room temperature or cooled, particularly
air, in the internal passage of the central tube, said roller
comprising an draining intermediate layer interposed between the
anti-adherent sheath and the cylindrical part, said intermediate
layer ensuring the evacuation of the thermal regulation fluid by
the lateral faces of the roller. The use of such a draining layer
combined with a by-inside cooling system makes it possible to
effectively maintain the sheath and the cylindrical part at
reasonable temperatures, below the deterioration temperatures of
the materials used.
[0024] Said intermediate layer is preferably formed from glass
fibres, carbon fibres, metallic fibres or threads, for example
copper or stainless steel, or polymer fibres, preferably
thermoplastic fibres, for example PAN or PEEK fibres, said layer
may be in the form of a non-woven fibre felt and/or in the form of
a fabric. The thickness and the grammage of the intermediate layer
are defined so as to ensure a passage of the gas flow sufficient to
remove the calories. In the case of glass fibres, the intermediate
layer forms an insulating barrier, limiting the rise in temperature
by conduction of the cylindrical part made of flexible material. In
the case of metallic fibres, the intermediate layer forms a barrier
to the radiation emitted by the heating system.
[0025] Preferably, said fluid communication means comprises radial
channels, each radial channel opening onto a radial hole in the
central tube and onto the external cylindrical surface of the
cylindrical part. The radial holes are distributed over the
cylindrical wall of the central tube. The central tube has for
example several sets of holes offset longitudinally along the axis
of the compacting roller, each set comprising a plurality of holes
made at regular angular intervals.
[0026] According to one embodiment, the head further comprises
thermal regulation means capable of delivering a flow of thermal
regulation fluid, in particular air, in the direction of the
compacting roller, in order to cool said compacting roller from the
exterior.
[0027] According to one embodiment, said intermediate layer
comprises glass fibres preferably in the form of a fabric, for
example in the form of a sleeve or braid.
[0028] According to one embodiment, the intermediate layer has end
portions extending beyond the cylindrical surface of the
cylindrical part, so as to guarantee the evacuation of injected
gas.
[0029] According to one embodiment, each lateral portion of the
sheath is assembled by its annular end section to the mechanical
assembly means.
[0030] According to one embodiment, each lateral portion of the
intermediate layer is assembled by its annular end section to the
mechanical assembly means. Mechanical means can be used alone or in
combination with thermoforming of the sheath, to assemble the
sheath and/or the draining intermediate layer. According to one
embodiment, the sheath is thermoformed and only the intermediate
layer is assembled via mechanical means. Separate mechanical means
can be used for the sheath and for the intermediate layer.
[0031] According to another embodiment, the intermediate layer is
glued to the cylindrical part, on the cylindrical surface and/or on
the lateral faces.
[0032] According to one embodiment, the mechanical means comprises
two washers, assembled to each other by assembly means, such as
screws, and between which the end section of the sheath and/or of
the layer intermediate is enclosed.
[0033] According to one embodiment, the roller has at each end a
portion defining a curved or inclined surface arranged in the
extension of the cylindrical surface, in order to obtain a
progressive folding of the sheath, this portion being formed of a
part added to the cylindrical part or being integral with the
cylindrical portion of the cylindrical part.
[0034] According to one embodiment, the head constitutes a fibre
placement head comprising cutting means and feeding means, and
possibly fibre blocking means. According to one embodiment, the
head is used to perform a filament winding type application.
[0035] According to one embodiment, said head further comprises a
is blowing system comprising an air blowing nozzle connected to an
air supply system, said nozzle being positioned upstream of the
roller relative to the movement direction, and is capable of
forming an air knife, preferably parallel to the axis of the
roller, in the direction of the nip point between the compacting
roller and the layup surface.
[0036] The head comprises a blowing nozzle delivering an air knife
in the direction of the nip zone, also called the contact zone, so
as to limit or even eliminate any deposit of combustion fumes on
the external surface of the roller. The air knife enables the
combustion flames to be extinguished by being blown out, or even to
eliminate the emergence of any combustion flames by blowing them
out. It is possible to blow out the flames with an air knife while
guaranteeing, despite the high air flow rate, a satisfactory fibre
layup quality, and efficient heating of the laid fibre(s), in
particular with a laser type heating system, without the need to
heat the air beforehand to form the air knife. This assembly of the
sheath combined with the blowing nozzle guarantees a good stability
of the sheath.
[0037] According to one embodiment, the blowing nozzle comprises a
longitudinal discharge slot arranged parallel to the axis of the
roller, or a plurality of outlets arranged along a line parallel to
the axis of the roller. This parallel arrangement makes it possible
to ensure an air knife at a high flow rate, sufficient to blow out
the flames, without altering the fibre layup quality, in particular
without displacing the fibres at the end of the trajectory.
[0038] According to embodiments, [0039] the blowing system is
capable of forming an air knife having a length at least equal to
half the length of the roller, preferably close to the length of
the fibre or the bands of fibres laid by the head, the air knife
preferably being centred relative to the roller; [0040] the blowing
system is capable of delivering an air knife at a flow rate of at
least 300 Nl/min, preferably at least 500 Nl/min, more preferably
at least 600 Nl/min, for example about 700 Nl/min; [0041] the
blowing system is capable of delivering an air knife at a flow rate
of at least 50 Nl/min per centimetre of air knife lengthwise,
preferably at least 100 Nl/min, more preferably at least 120
Nl/min; and/or [0042] the air blowing nozzle is connected to a
supply source formed by a compressed air source or to a turbine,
preferably mounted on said head, delivering pulsed air.
[0043] According to one embodiment, the head comprises a laser type
heating system, in particular laser diodes, a YAG laser or a fibre
laser, capable of emitting a laser beam in the direction of the
contact zone between the roller and a layup surface. Alternatively,
the heating system may include one or more infrared lamps.
[0044] The present invention also relates to a method for
manufacturing a composite material part comprising the application
of continuous fibres onto an application surface, characterized in
that the application of fibres is carried out by means of a fibre
application head as described previously, by relative displacement
of the application head in relation to the layup surface along
layup trajectories, the fibres being compacted during their
application by means of said application roller.
[0045] The fibres conventionally used are continuous flat fibres,
also called tows, generally unidirectional, and comprising a
multitude of filaments. The laid fibres can be dry fibres or fibres
pre-impregnated with thermosetting or thermoplastic resin. The
fibres typically have widths of 1/8, 1/4 or 1/2 inch. As used
herein, the term "fibres" also refers to fibres of greater width,
greater than 1/2 inch, conventionally called band in placement
technology.
[0046] The method according to the invention is particularly
advantageous in the case of the production of dry preforms produced
from dry fibres provided with a binder and/or thermoplastic
preforms produced from fibres pre-impregnated with thermoplastic
resin, requiring high heating temperatures during layup to at least
reach the melting point of the binder and/or the thermoplastic
resins.
[0047] In the case of a dry preform, the method further comprises a
step of impregnating resin into the dry preform, by adding one or
more impregnating resins by infusion or injection to the dry
preform, and a curing step to obtain a composite material part. In
the case of a thermoplastic preform, the preform may possibly be
subjected to an additional consolidation step to obtain a final
composite material part. In situ consolidation can also be obtained
during the application of the fibres.
[0048] The application of fibres can be carried out on the
application surface of a tool to form a preform, such as described
previously, by fibre placement, band placement, and/or winding.
According to another embodiment, the application of fibres is
carried out directly on the application surface of a prefabricated
part, to reinforce this part with unidirectional fibre
reinforcements, the prefabricated part being for example a part
obtained by injection, molding or additive manufacturing, from one
or more thermoplastic and/or thermosetting resins.
[0049] The invention will be better understood, and other
objectives, details, characteristics and advantages will appear
more clearly in the following detailed explanatory description of a
currently preferred embodiment of the invention, with reference to
the schematic drawings annexed thereto, in which:
[0050] FIG. 1 is a schematic side view of a fibre application head
according to the invention, illustrating the compacting roller, the
heating system and the blowing system;
[0051] FIG. 2 is an enlarged partial view of FIG. 1;
[0052] FIG. 3 is a schematic perspective view, with a partial cut
away, of the compacting roller of FIG. 1;
[0053] FIG. 4 is a perspective view of a compacting roller with a
partial cut away, according to a second embodiment;
[0054] FIG. 5 is a perspective view of a compacting roller
according to a third embodiment;
[0055] FIG. 6 is a perspective view of a compacting roller, with a
partial cut away, according to a fourth embodiment;
[0056] FIG. 7 is a perspective view of a compacting roller, with a
partial cut away, according to a fifth embodiment; and,
[0057] FIG. 8 is a perspective view of a compacting roller, with a
partial cut away, according to a sixth embodiment.
[0058] With reference to FIGS. 1 and 2, the application head 1
comprises a compacting roller 2 which is mounted to rotate around
an axis A on a support structure of the head. The head is intended
for the application of a band formed of several fibres arranged
side by side. The head is mounted by said support structure at the
end of a movement system, for example a robot wrist joint. The head
further comprises a heating system 9 also mounted on the support
structure, upstream of the roller relative to the advancement
direction D of the application head during the application of a
band of fibres F onto an application surface. S. The heating device
is for example a laser type heating system, the radiation of which
is directed towards the band, just before its compaction, as well
as towards the band(s) already laid.
[0059] As illustrated in FIG. 1, the radiation 91 is thus directed
obliquely towards the nip zone or contact zone between the
application roller and the application surface, to heat a section
of the band located on the roller, before its compaction by the
latter, as well as the application surface and/or one or more bands
previously applied.
[0060] In the case of a fibre placement machine, the head comprises
guiding means 11 which guide the fibres entering the head towards
the compacting roller 2 in the form of a band of fibres, the fibres
of the band being arranged side by side in a substantially
contiguous manner By movement of the head by the robot, the
compacting roller is brought into contact with the application
surface of a mold S to apply the band.
[0061] The fibres are preferably flat continuous fibres, of the
tows type, pre-impregnated with a thermosetting resin or a
thermoplastic resin, or dry fibres provided with a binder. The
binder is in the form of powder and/or one or more veils,
preferably of the thermoplastic type.
[0062] According to the invention, the head further comprises a
blowing system 8, comprising a nozzle 81 also mounted on the
support structure, upstream of the roller relative to the
advancement direction D, capable of emitting a knife blade of
compressed air towards the contact zone. The nozzle forms an air
knife, parallel to the axis of the roller centred along a direction
illustrated schematically under the reference 82. The nozzle is for
example connected to a compressed air supply circuit.
[0063] With reference to FIG. 3, the compacting roller 2 comprises
a cylindrical part or body 3 made of a flexible material,
elastically deformable by compression. The cylindrical part has a
cylindrical central passage for its assembly on a support core
formed by a rigid cylindrical central tube 4, for example metallic,
such as aluminium. The cylindrical part 3 and the central tube 4
are coaxial and are integral in rotation with one another. The
cylindrical part here comprises a single cylindrical part with a
cylindrical surface 33 and two lateral faces 34.
[0064] The cylindrical part 3 of flexible material gives the
compacting roller a crushing capacity which enables the compacting
roller to adapt itself to variations in the curvature of the
application surface and thus to apply a substantially uniform
pressure over the entire laid band. The rigid tube enables the
rotary mounting of the roller on the support structure.
[0065] The cylindrical part is for example comprised of an
unexpanded elastomer, such as a silicone or polysiloxane, or a
polyurethane, preferably a silicone, for example a two-component
silicone which can be polymerized at room temperature. The
cylindrical part has a hardness between 30 Shore A and 70 Shore A,
for example 40, 50 or 60 Shore A, which will be chosen according to
the desired crushing rate of the roller for a given compaction
force, this crushing rate being defined in particular according to
the complexity of the application surface.
[0066] The central tube is provided with radial holes 41, for
example cylindrical, traversing the cylindrical wall of the central
tube from end to end. The radial holes thus open onto the internal
passage 42 of the central tube and onto the cylindrical part. The
latter is provided with radial channels 32, aligned with said
radial holes 41, having diameters substantially identical to those
of said radial holes. Each radial channel 32 opens onto the
external cylindrical surface 33 of the cylindrical part 3. By way
of example, the central tube comprises six sets of radial holes 41
offset longitudinally along axis A of the roller, each set
comprises a plurality of radial holes arranged at regular angular
intervals, for example eight radial holes at 45.degree. to one
another. The cylindrical part then comprises six sets of radial
channels 32 each comprising eight radial channels at 45.degree. to
one another.
[0067] The cylindrical part is coated with a draining intermediate
layer 5, here formed of a glass fibre fabric, for example in the
form of a sleeve or braid. The intermediate layer has a certain
elasticity to follow the deformations of the cylindrical part when
the roller is pressed against the application surface.
[0068] The intermediate layer is externally coated with an external
anti-adherent sheath 6, formed here of a heat-shrunk PFA film on
the surface of the cylindrical part, with the draining intermediate
layer interposed between the cylindrical part and the sheath. The
anti-adherent sheath through which the roller is in contact with
the band, limits the adhesion of the roller to the fibres, as well
as the fouling of the roller.
[0069] According to the invention, the anti-adherent sheath has
lateral portions 61 extending beyond the cylindrical surface along
the lateral faces 34 of the cylindrical part.
[0070] The anti-adherent sheath is formed from a tubular film of
greater length than that of the cylindrical part, which is fitted
onto the cylindrical part then thermoformed, so that the lateral
portions are at least partially flattened along the lateral faces.
The lateral portions thus heat-shrunk ensure the blocking in
translation and in rotation of the anti-adherent sheath and of the
intermediate layer on the cylindrical part.
[0071] The intermediate layer 5 also has lateral portions 51
extending beyond the cylindrical surface and which are inserted
between the lateral faces 34 and the heat-shrunk lateral portions
61 of the sheath.
[0072] The mounting of the roller on the head is carried out by
means of an axial rod 21 mounted in the internal passage of the
central tube 4 by means of two ball bearings 24, the central tube
advantageously having a counterbore at each end for the mounting of
a bearing. The roller is then mounted by the ends of the axial rod
between two flanges 12 of the support structure of the head.
[0073] The machine comprises thermal regulation means (not shown),
making it possible to inject a gas at room temperature, between 15
and 30.degree. C., or a gas cooled to a temperature below
15.degree. C., in particular air, through one end of the axial rod.
The axial rod 21 has an axial passage 22 opening onto one 25 of the
ends of the rod, and a radial bore 23 enabling said axial passage
22 and the internal passage 42 of the central tube to be placed in
fluid communication, between the two bearings, the two bearings
being sealed bearings.
[0074] In operation, the air injected through at least the open end
of the axial rod, arrives in the internal passage 42 between the
two sealed bearings, passes through the radial holes 41 then the
radial channels 32 of the cylindrical part, then passes through the
draining intermediate layer 5 and escapes laterally through the
lateral portions 51. This injected air makes it possible to
uniformly cool, the cylindrical part of flexible material, as well
as the sheath.
[0075] The laser type heating system can comprise laser diodes,
arranged in one or more rows, emitting radiation of a wavelength(s)
between 880 to 1030 nm for example, a fibre optic laser or a YAG
laser, emitting a wavelength of around 1060 nm.
[0076] The air knife from the blowing system 8 blows out the resin
combustion flames, more precisely extinguishes by blowing out the
flames that may appear during laser heating, or even eliminates the
emergence of any flames by blowing them out. Thus, the air knife
makes it possible to limit or even to eliminate any pollution of
the sheath linked to combustion.
[0077] For example, the head is equipped with a compacting roller
having a length of approximately 6 cm, intended to layup a band of
8 fibres of 6.35 mm (1/4'' inch). The nozzle comprises a row of
charging outlets forming a knife of approximately 5 cm at the
nozzle exit. The nozzle is supplied with compressed air at 5 bars,
equivalent to an air knife at a flow rate of approximately 700
Nl/m.
[0078] FIG. 4 illustrates a second embodiment of the invention in
which the compacting roller 102 comprises as previously a rigid
central tube 104 provided with radial holes, a cylindrical part 103
made of elastically deformable flexible material provided with
radial channels, an intermediate layer 105 with lateral portions
151, and an anti-adherent sheath 106 thermoformed with lateral
portions 161.
[0079] In this embodiment, the cylindrical part comprises a central
cylindrical part extending laterally via two annular flanges 134
whose outer surfaces form a continuous surface with the cylindrical
surface 133. The cylindrical portion and the lateral flanges are
molded into one piece, the flanges having a cylindrical outer
surface. The lateral portions 151, 161 of the intermediate layer
and of the sheath are arranged on said is flanges 135. During the
thermoforming of the sheath, the flanges progressively fold inwards
in the direction of the lateral faces of the cylindrical part, such
as illustrated in FIG. 4. The flanges allow the sheath and the
intermediate layer to be folded over a non-sharp edge at the end of
the cylindrical part, and thus to avoid deterioration of the sheath
over time at the level of the folding.
[0080] FIG. 5 illustrates a third embodiment of the invention in
which the compacting roller 202 comprises as previously a rigid
central tube 204 provided with radial holes, a cylindrical part 103
of elastically deformable flexible material provided with radial
channels, an intermediate layer 205 with lateral portions 251, and
an anti-adherent sheath 206 thermoformed with lateral portions
261.
[0081] In this embodiment, as a replacement for the aforementioned
flanges, the roller comprises a O-ring seal or part 235 arranged
against each lateral face 234 of the cylindrical part, and the
anti-adherent sheath 206 is heat-shrunk over said seals. The seals
have an outside diameter equal to the outside diameter of the
cylindrical part and enable the sheath and the intermediate layer
to be folded over a non-sharp angle at the end of the cylindrical
part. Preferably, the cylindrical part has a small flange at the
end to ensure perfect surface continuity between the cylindrical
surface of the cylindrical part and the seal.
[0082] Furthermore, the assembly by heat-shrinking is here
completed by mechanical assembly by means of two washers 271, 272
assembled together by means of screws 273 by enclosing the annular
end sections of the lateral portions 251, 261 of the sheath and of
the intermediate layer between them.
[0083] The washers are pressed one against the another by contact
zones angularly spaced to one another, to enable the evacuation of
the air flow by the lateral portions of the intermediate layer
between two contact zones. For this purpose, at least one or both
of the washers are ringed, or one or both of the washers have, on
their opposing faces, bosses or studs distributed at regular
angular intervals, for example at the holes of the outer washer
and/or the threads of the inner washer which serve for screwing in
the screws, the washers being pressed one against the other by said
bosses when tightening the screws.
[0084] FIG. 6 illustrates a fourth embodiment of a compacting
roller 302 which differs from the preceding compacting roller 202
in that the two annular washers 371 have tabs 371a arranged at
regular angular intervals and extend radially towards the exterior,
the two washers are assembled to each other by means of screws 373
screwed into said tabs, enclosing between them the end portions of
the anti-adherent sheath and of the intermediate layer. Thus, in
this embodiment, the air injected from inside the tube escapes
through each zone of lateral portions of the intermediate layer
arranged between two adjacent tabs.
[0085] FIG. 7 illustrates a fifth embodiment of a compacting roller
402 which differs from the compacting roller 102 illustrated in
FIG. 4 by the fact that, on each side of the roller, the annular
flange 435, the lateral portion 451 of the intermediate layer 405,
as well as the lateral portion 461 of the sheath 406 are assembled
together by mechanical means. These mechanical means comprise an
outer washer or crown 471 provided with inclined tabs 471a at
regular angular intervals, and a washer or inner ring 472 provided
with an inclined annular surface 472a, the crown and the ring being
assembled to each another by screws 473, so that the flange and the
two lateral portions 451, 461 are enclosed between the inclined
tabs and said inclined surface of the ring.
[0086] FIG. 8 illustrates a sixth embodiment which differs from the
embodiment of FIG. 3 by the fact that, on each side of the roller
502, the central tube 504 has an end section 543 extending beyond
the lateral face 533 of the cylindrical part 503, the lateral
portion 551 of the intermediate layer 505 extends beyond the
lateral portion 461 of the thermoformed anti-adherent sheath 506,
over the whole of the lateral face of the cylindrical part 533, and
is blocked on the end section 543 of the tube by means of a ring
571. For example, the ring is crimped or screwed onto the tube, or
is formed of two half-rings assembled by u) screwing. In this
embodiment, the sheath is held in place only by thermoforming, only
the intermediate layer is assembled by mechanical means.
[0087] Although the invention has been described in connection with
various particular embodiments, it is obvious that it is not
limited thereto and that it includes all the technical equivalents
of the means described as well as their combinations if they are
within the scope of the invention.
* * * * *